Gneiss
Gneiss
metamorphic
Category
Mineral (Tectosilicate)
Browse mineral (tectosilicate) specimens identified by the Rock Identifier community.
River Stone (Granitic Gneiss)
Foliated Granitic Gneiss
metamorphic
Charoite
Charoite (Hydrated potassium, sodium, calcium, barium, strontium silicate hydroxide fluoride)
metamorphic
Granite Pebble
Granite (Phaneritic intrusive igneous rock)
igneous
Granite (Pink/Red)
Phaneritic Plutonic Felsic Rock (major minerals: Quartz, Orthoclase Feldspar, Plagioclase Feldspar)
igneous
Granite
Plutonic felsic rock (Quartz, Feldspar, Mica)
igneous
Gneiss (Granitic Gneiss)
Gneiss (composed primarily of Quartz, Feldspar, and Mica/Amphibole)
metamorphic
Diorite (River Rock)
Intermediate plutonic igneous rock
igneous
Quartz Pebble (with probable inclusions or staining)
Quartz (Silicon Dioxide - SiO2)
mineral
Granite (with Orthoclase and Quartz)
Phaneritic Felsic Igneous Rock (KAlSi3O8 + SiO2)
igneous
Sandstone (Greywacke)
Arenite / Clastic Sedimentary Rock
sedimentary
Diamond (Macled/Crystal fragment)
Carbon (C), isometric crystal system
mineral
Granite featuring Quartz Vein
Granite with hydrothermal silica (SiO2) intrusion
igneous
Granite
Granite (Phaneritic igneous rock)
igneous
Basalt
Aphanitic mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
igneous
Granite
Granite (composed primarily of Quartz SiO2, Feldspar KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8, and Mica)
Igneous
Howlite and Purpurite druzy
Calcium Borosilicate Hydroxide (Howlite) and Manganese Phosphate (Purpurite)
mineral
Tumbled Moonstone
Feldspar (Orthoclase/Albite), KAlSi3O8
mineral
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Turquoise
CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminium)
mineral
Satin Spar (often sold as Selenite)
Gypsum (CaSO4·2H2O)
mineral
Sandstone
Arenite (SiO2 primarily)
sedimentary
Aquamarine
Beryl (Be3Al2Si6O18)
mineral
Quartz (Milky/Clear variety)
Silicon Dioxide (SiO2)
mineral
Botryoidal Chalcedony (Agate/Desert Rose Chalcedony)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Citrine Quartz
Silicon Dioxide (SiO2)
mineral
Amethyst
Amethyst (Silicon Dioxide - SiO2 with ferric iron impurities)
mineral
Amethyst (Polished/Carved Crystal)
Silicon Dioxide (SiO2) with trace Iron (Fe)
mineral
Druzy Quartz on Limestone
Silicon Dioxide (SiO2)
mineral
Amethyst
Amethyst (Varietal of Quartz), SiO2 with traces of Iron (Fe3+)
mineral
Agate Geode with Quartz Druzy
Chalcedony (SiO2) and Quartz (SiO2)
mineral
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
metamorphic
Quartz (specifically Clear Quartz with iron/hematite staining)
Silicon Dioxide (SiO2)
mineral
Petrified Wood
Silicified wood (primarily SiO2 - Silicon Dioxide/Quartz)
metamorphic
Amethyst (Quartz)
Silicon Dioxide (SiO2) with iron impurities
mineral
Clear Quartz Cluster
Silicon Dioxide (SiO2)
mineral
Smoky Quartz
Smoky Quartz (SiO2)
mineral
Ocean Jasper
Orbicular Jasper (Silicon Dioxide with impurities), SiO2
mineral
Emerald
Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)
mineral
Ferruginous Quartz
Quartz (Silicon Dioxide) with Iron Inclusion, SiO2
mineral
Gold-bearing Quartz
Native Gold (Au) in Quartz (SiO2) matrix
mineral
Quartz Vein in Siltstone
SiO2 (Quartz) on clastic sedimentary matrix
sedimentary